The output of a PV installation depends upon maintaining the health of the PV modules that comprise the installation. A number of factors affect the health of PV modules. Such factors include infiltration, soiling, shading, ionizing radiation, interconnect integrity, electrostatic discharge, temperature stress, coating degradation, theft, bypass diode failure, and manufacturing variation.
PV installation monitoring provides information about the health of an installation and thus supports its maintenance and repair. Conventional methods that monitor the active output current of PV strings provide useful information about string-level health but are unable to distinguish between electrical and illumination issues, can not measure health at the substring or module level, and can not determine the health of the bypass diodes.
Unlike conventional methods the invention provides a system and method for monitoring both the active and passive characteristics of the strings that comprise PV installations in order to better distinguish between health issues caused by illumination issues and those caused by electrical issues. Unlike conventional methods the invention further provides a system and method for monitoring substring and module health in order to better isolate the location of health issues.
Previous systems and methods for monitoring PV substrings and bypass diodes have required the installation of either costly equipment or costly wiring. Unlike previous systems and methods, the invention is capable of monitoring substrings and bypass diodes at a low incremental equipment cost and low incremental wiring cost.